Power-operated breech mechanism.



D. F. ASBURY.

POWER OPERATED BREECH MECHANISM.

APPLICATION FILED on. 4. 1915.

1,229,859. Patented June 12, 1917.

3 SHEETS-SHEET l.

I D- F. ASBURY.

POWER OPERATED BR'EECH MECHANISM.

APPLICATION FILED 00L 4. 19].;-

1,229,859. Patented June 12, 1917.

3 SHEETS-SHEET 2.

D. F. ASBURY.

POWER OPERATED BREECH MECHANISM.

APPLICATION FILED OCT. 4, I915.

Patented Jun 12, 1917.

3 SHEETS-SHEET 3.

- J run: 111' oz uni/awr UNITED STATES PATENT orrron.

DOBSEY F. ASBURY, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TOUNITED STATES ORDNANCE COMPANY, OF WASHINGTON, DISTRICT OF COLUMBIA, A 003- PORATION OF VIRGINIA.

rownnrornnarnn BREECH MECHANISM.

Specification of Letters Patent. Patented fine 12, 1917- Application filed October 4, 1915. Serial No. 53,962;

To all whom it may concern Beit' known that I, DoRsErF. AsBURY, a citizen of the United States, and resident of the city of Washington, in the District of Columbia, have invented certain new and useful Improvements in Power-Operated Breech Mechanisms, of which the following vide a hydraulic control brake that will ar rest the opening swing of the mechanism and control the swinging of the. breech mechanism toward the gun breech and finally arrest the movement of the operating parts when the mechanism -is'closing; to provide means that will prevent the hydraulic piston rod packing from being under the hydraulic brake pressure; to provide a hydraulic brake piston that moves with the entire stroke of the operating motor piston and controls all movements,v of the mechanism due to said motor or gravitation; to combine the hydraulic and motor cylinders-into one unit; to so construct the motor and hydraulic brake cylinders thatthe'fluid fromeither cannot leak into the other; to provide a trap so that the liquid in the hydraulic brake reservoir will always he at atmospheric pressure and which also will prevent any leakage from the reservoir during recoil and counter -recoil of the gun; to provide a rotating cam on the plug rotating crank shaft and a cam follower on the gun whose coaction is in har- 40 mony with the coaction of the breech plug rotating cams; to' extend the crank shaft cam so that its coaction withthe cam follower on-the gun holds the crank shaft from rotating dur ng the swing of mechanism not affected by the plug rotating cams action; to have the cam on the shaft in engagement with the roller onthe gun before the plug and screw box threads have disen latch face is out of I contact with the latch face on the crankshaft cam; to taper one side of the extension of the crank shaft cam so that its coaction .with thecam follower I will gradually move the latch face on' the crank shaft cam out of contact with the latch face'of the latch before the latter is operated to or from locked position; to

providemeans for assembling and holding together the crank and cross head bearing; and to provide means for moving the cross head bearing fore and aft in harmony with' the fore and aft movement of the breech plug'due to the lead of the plug threads.

In the drawings chosen for the purpose of illustrating my invention, the scope whereof is pointed out in the claims,

Figure 1 isa view in, elevation of the breech end of a. gun embodying my invention, the breech mechanism being shown closed and locked and the operating motor and hydraulic brake "in section; I Fig. 2, a plan view of the gun shown in Fig. 1;

Fig. 3, a partial plan view of the gun with the parts in the position they would.

occupy when the plug rotating cam is just beginning to act in opening the breech or just finishing its action when closing the breech; v 1 Fig. 4, a section on the line 4-4 of Fig. 1 with the parts in the position they would occupy when the plug rotating cam is justbeginningto act' in closing the breech or just finishing its action in opening the breech; I

Fig. 5, a partial plan view. with the breech" fully open Fig. 6, a section on the line 66 of Fig." 7, a section on the line 77 of Fig. 1. a

rear portion of the gun, B the plug, and C the carrier, which latter swings on trunnions'10 mounted respectively in upper and lower bearing brackets 11. Cam devices 'M and; N are provided for the purpose of translating the breech and for initiating the swing of the carrier in opening the breech. Each of the movement of the plug in closing v these tam} devices com rises-Ia: roller-12 1- mounted' on the: gun an af'camj member '13 mounted on the "plug, The 'detail arrangeg 'ment and construction 'of said rollers, and cam- .members are full "setfiforth in" my United States-Patent June 6, 1916.

which latter will presently appear. [Pivotaljly connectedto the reareface of the plug v mcrossheadf which 0 eratively-receives' the locking and unlocking-rotations-of the sh I sion 17 or thecrank 15 or over both-the exi tension and the crank .which; "assures the" crank pin '16.}- Inor erflto hold the. crank; 15, cross-head bearing 19, andcrfossehead 20 in assembled r'elationI provide the bearing 19 with an inwardly extendingzl flan'ge "21' -which, in the locked position of the plug,

overlies the extension 17 and as the-shaftfl4' is rotatedin"- unIocking-' the plug: said flange passes into overlying relation to theacrank'.

15. It will thus be seen that during the; 111

14 the flange 21 i's'disposed over the extenparts beingv held in proper assembled relation during f-operation; The provision'of the extension-17 and flange 21 also fenables the cros's-head bearing and cross-headto be a easily] removed from :the, crank I5 that,

moved and the pitman,swung.away from the t when downward moyement of the cross-head bearing. and-cross-head'will completely-dis r reversal-ofthisjoperation likewise afifordsf an easy and "simple means for assembling engage same jfroln the crank and crank pin.

7 *the parts, T9 Provide-means for'moving the 1 cross-head bearing fore and aft in. harmony .with the fore and Jafkmo'vements' 'of the breech 'pl-ug du'eat'o the lead of theuplug'o threads, I provide thefflange 21 with an'. in,-'.':' -.clin'ed face 22 -.which, .dllring the unlockin J rotation I off'the 'plug, ;'cooperates with. an iiif;-

clined face- 23 on: the-carrierto move-wthej' cross-head aft To move the cross" head bearingforward during} locking rota-- tion "of the plug I- provide the cross-head .ibearing with another inclined face 24 which.- coiiperates with the adjacent face of the "crank 15-. An inspection of Fig. 6-will show that the aft movement of the-cross-head' bearing due to the -coaction of the inclined faces 22 and 23 during plug unlocking movement of the pitman18 will so' position; the

.b-,- 5 e r I -movementxof t Rotatably mounted inrthe' carrier C is a-- .shaft 14. the axis offlrotation-of which is. g arallel to the pivotal axis of the carrier. a he lower e d of this-shaftjembodies a crank} 1'5 which in ludes a depending crank pin-"1'6- {"substanti and a lateral extension 17 the purpose jof' end" {of which is 'mo plug threads. a

- Fixed on the upperendof shaft 14 is v 1 a control cam in' the for'n 1 of an'tarm .25

inclined face 24 with' re'spectto thadjaeeht "face of the crank that during" opposite move ment' of the pitma'n the coaetion of thefa'ce 24withthe adj a'centface ofthefcrank will impartfa forwardmovement toi llhe cross? head bearing in harmony with the forward he plugdue'to'the lead. of the I 7 which is qrovided' .onv its finder-Side ,j'With-a a mediate point therein'toits outer end. ;Qar

. 1y r' ep dagm v i Li di -P. :1 tions;26 and 27 theouter ends of'which'open through fthe same sides f'the arm25. The groove section '26 formscam walls 28 and 28' each'of which "is shaped inharmony with 1.th e; cam faces of themembers 13,-- while the .grOoVe'section 27 forms'a holding. wall 29 .which-diverges'with res ect to the opposite wall of the groove sectlon from an mterriedfbythe upper bearing bracket 11- is a 1 rearwardly -prqect" g arm 30 on the outer travels'in the groovesections26 and "27' and cooperates directly with the-walls 28 and 29 Iduring opening and closing of the breech j mechanism for a purpose. that will presently Vt-38,1... j, x j I I ounted onthe'br'e'ech endofthe A is a'bracket 321 on 'which- 'is-pivoted a motor a roller 31 which 2 cylinder-33; Disposedwithinthemotor cylindex--33 the section34 off a hydraulic end ahead 35 which is threaded in'the mohead 35 is a-hydraulic brake reservoir 36 which-has dis osed therein'and formed inin g"with the brake cy inder section 34'and brake'cylinder; said sectionfhaving at one- 1; I f-tor cylinder33 and forms one endof the 1 j i I ;latter. Threaded t0 thePoutenend of the when theplug .isilocked',;the pivotal connecitionbetweenthepitman and plug can be re-.

pluga'sli ht distance to-inove the, flangef121- from-overying relation to the extension 17?, 5 I

forming-in conjunction therewith the complete brakecylinderc Communication be-' ytween the reservoir-36 and the interior of I the brake 'cylinder'is afforded-by means ofiiilss ges 38- and 39 fornied'inthe section ,37 offthe brake cylinder; {Mounted in the pas- I {sage 39.is a ball check valve :40 whichserves to prevent; .flow of liquid from the brake reservoir 36 at atmospheric-pressure while the provisionof" the air pocket-or trap 43 effectually guards against anyv leakage of fiquid fromthe reservoir-duringrecoil or 115 7 cylinder to the reservoir through the pas 3 -j I -sage 39 while permitting free flow of liquid.

" fromfthe reservoirto [the brake cylinder. The-,wall of l-the----reservoir' 36'is provided" with a filling'opening 41 in which is detach- 1 ably threaded a lug-42 having a reduced; 'central' ;po1-tion'.- orming -an air ocket or the piston head and-the other end throughcounter-recoil of the gun. I Slidable on the other end terminates in a piston head 48'.

Air is supplied to and exhausted from opposite ends of the cylinder. 33 to effect reciprocation of the rod 46 and piston .head 4.8 by means of. pipes 49 and 50. These pipes lead to a point directly above the pivot of the cylinder 33 which permits-rigid connection, the oscillations of the cylinder .being accommodated by the resiliency of the pipes. Slidable in the brake .cylinder is a piston rod 51 which has one end connected with the piston rod 46 for movement with the latter while the other end terminates in a piston head 52. The rod 51-slides in a packing 53 suitably mounted in the end of the brake cylinder section 34 remote from the reservoir 36. Formed in the rod 51- and piston head 52 is a by-pass 54, one end of which opens through the reservoir end of the side of the iston rod 51-. Mounted in the end of the y-pass 54 is a ball check valve 55 which prevents flow of liquid through the by-pass' during movement of the piston head toward the reservoir or in other words during breech closing movement of the piston head .52. Provided within the brake cylinder section 34 is a circumscribing flange 56 which divides the brake cylinder into chambers 57 and 58.

adapted to engage the' rear end of the gun, when the breech mechanism is fully locked. During the first portion of the closing swing,

of the breech mechanism the stop' 59 holds the arm 25v and shaft 14 against rotation and relieves both the shaft and arm of part of the strain. During the last portion of the opening swing of the breech mechanism the arm and shaft are held against rotation by means of a latch 61 pivoted on the carrier. This latch embodies at one end divergtoes 62 and 63 and at its other end a nib 64 adapted to cooperate with a latch face 65 on the arm 25 when said latch is in locked position. The movement of the latch 61' to locked and released positions is automatically effected during the swing of the 'carrier and to this end I provide a lug 66 on the upper bearing bracket 11 which co6perates with the toe 62 and I further provide of the mechanism to roc the. latch to locked position. During closing swing of the mechanism the lug 66 engages thetoe 62an rocks the latch to and subsequently holds same in released position until'the next opening swing of the mechanism. When the arm 25 is disposed against the. stop 59 and the latch 61 operated to locked and released positions there will be a slight clearance between the latch face 65 and nib 64 to permit of such operation of the latch without any hardcontact between said latch face and nib. I The arm 25 is held in proper p0 sition during the operation of the latch 61 by engagement of the roller 31 with the wall 29 aswill be more fully set forth" in the detail description of the operation of the mechanism. v

' For the sake of clearness I will first describe the operationof opening and closing the breech mechanism without reference to the hydraulic brake. when the mechanism is fully locked as shown in Fig. lcompressedair is admitted to'the cylinder 33 through the pipe 49. This air will. act against the piston 48 to force same and the rod 46toward the opposite end of the cylinder and at the same time air in advance" of the piston 48 will be relieved through the pipe 50. This movement of the rod 46 acting through the arm 25 will rotate said am and the shaft 14 to the position shown in Fig. 3. vWhen the parts reach this To openthe breech 1 position the coaction of the cam devices M and N begins and likewise the coaction of the roller 31 with the wall 28. As this wall 28 is shaped in harmony with the cam faces of the members 13 it will be obvious that the shaft 14 can only move in harmony with those movements of the breech plug resulting from the coaction of said cam devices M and N. As the wall 28 is also shaped in harmony with the cam faces of the'members 13 it is also obvious that the movements of the plug and carrier due to the coaction of the cam faces 13 with the rollers 12 will have 'to- .be completed before the mechanism can swing out beyond such opening swing as is imparted to it by the coaction of the cam devices M and N. When thecam devicesM and N reach'the termination of their coaction the partswillassume the position shown in Fig. 4 and the roller 31, upon further opening swing of the carrier by the motor,

will pass into the groove section 27 and against the wall 29. y This engagement of the roller 31 with the wall 29 holds the arm '25. vDuring this holding of the arm 2 5.by means of the engagement of the roller 31 with the wall 29the toe 62 of the latch 61 rides up the lug 66 and finally passes out of ment ioflthe latch to locked position as just described the arm 25 is'held by engagement of. the roller 31 with the wall 29 so that no i [position the roller 31 moves alongjthe ta-- pered; 'ortion of the wa1l 29' and thereby; j gradua ly releases the latch face --65 into con- 13' tact with the nih 64'and prevents any-sudden.-

strain being exert dp t Pivot n-1 3 the latch 61. Continued movement of 5' the 7. rod 46-.vwill then' swing the mechanism to .full' open position as shown in Fig. 5, the latch ing movement of theme'chanism. v

' 'To lose the breech mechanismcompressed Q air admitted to -thefc'zylindei}'35 through the pipe 50 while the airon the'oppositeside of the. piston 48 will be-relieved through the pipe 49. '.The resulting movement of the piston] 48 and the piston; rod .46 acting through the step 59-wil1 initiate the closing fiswing of the" mechanism.

movement;of the mechanism the ro er 31 wi llenter the groove section27 and bear against the'wall 29 to hold the "arm 25 in proper position duringthe operation of the latch 61. While theroller 31 is in engage-'- ment with the wall 29 and just before said.

roller begins to coact with the wall '28 the free end of the toe-63 reaches' thelimits of the recess 67 while the-mesa engages the lug 66 with the result that further-swing-ofthe mechanismwill cause the'lug 66 to rock the?- .1 latch 61 to release position, such movement of the latch of-course occurring while-the. nib 64 is out of hard-contactfwith the latch to face 65. Following the movement- 'gof the flatch' 61 torelease position the'roller 31 be gins tocoiiperate'withithe wall28 and at i j -thesametime the-*cam'devicesM and'N be-' to coact to initiate the IOCk L grTOtatiOn of the plug. During this coaction of the cam devices M and N the movements of the shaft 14' will be rendered corresponding .to the movement of the plug 1,B'.prod'uced by the cam devices M- and N as a' resultlof the coac--- '50 tion of the roller 31 with'thewal1 28'. At the same time that the Tcoaction of the camde-' vices M and 1ST to rotate the plug B ceases the roller 31-will assout of the groove sec-v ".,-tion- 26-.when."furt er movement of. the ie-1 .55 ton rod 46 will rotate thearni 25 and the 4 shaft 1 4to .the'pos'ition shown'in Fig.- 2 and 1 qmple eth I will now describe"- actionof the hy' the hydraulic brake device-will be in the po sition shown in Fig, 1 and as the piston rod I 51 is connected. to the piston rod 46-it will Durin this lockingofthe breech m'e'cha wa 3 a free'stroke'of-the piston during the unlock- 1. 61fservin mlock the arm 25 and theshaft 5' 14 agains rotation during such final open ing ofthe breech mechanism, the coaction of the'cain devices Mand. N, and the first portion of the opening swing of the mech- I 'aliism, at ,which. time it will'be. obvious the greatest power is required to'actuate the parts of the mechanism; Asthe mechanism approaches its fullo'pen position the advance end of th'eby-passfl-54 -moves;by the flange 56 and into the chamber 58 so that the liquid which-is between the piston 52 and flange 56 canno longer flow; directly through said by-pass. to the reservoir end ofthe piston 52. The liquid which is now between the piston 52 and the flange 56 must therefore throttle by 1 the piston 52' and by. the flange 56 and the 'res1'stanceofiered to this throttlingfof the-liquid controls the final opening -movements -''of the, breech mecha-f nism'so that same brought gently to rest in full open position. .The provision of the chamber 58 also serves to preventthe packing 53 -from beingjsubjected to' brake pressure when the openingswingof the mechanism is being" arrested fori'itj. will be objivieus that tthexliquid throttled into the chamber 58acangpass-freely tothe reservoir end of the pijston152 :through the by-pass 54 and thusprevent the {piessureof the liquid in the -chamber.,.58 .from increased. 'During the movement-hf :the 'iston '52 just described a vacuum will, be in the 1 brake cylinder at the reservoir end thereof andif provision isnot-ma'deto relieve this vacuu'ma throttlingof air; bynthe packing 53 into thebr'akecylinder will result. I- prevent this suction throttling" through the Imedium of the passage 39 and check valve reservoir "to the brake cylinder during the stroke of the piston referreditob In other words. I "automatically increase the area of communication between the brake cylinder v and -.reservoir so that-fisufiicient liquid can flow fremithe reservoinfinto the brake cyl inder underthe -'conditions named to relieve the vacuum;- and prevent suction .throttling. It will 'b'e'noted that'the diameter of that portion of the chamber 34' through which i the piston-52' passes after. theby-pass enters into communication with the chamber 58 is reduced so 'asto afford the necessary re- 85is thereby had to bring the sistan'ce to the throttling of the liquid by the piston 52 to produce the requisite braking effect for arresting the opening swing of the mechanism. It will also be noted'in this. connection that the diameter of the chamber 57 at the end thereof remote from the flange 56 is also reduced'sfor a purpose that will clearly appear from the detail description of the breech closing operation of the brake device.

In closing the breech mechanism it will be apparent that the check valve 55 will preventfiow of liquid through the by-pass 5 L which necessitates the liquid throttling by the piston 52 and produces a control stroke which prevents abnormal velocities of swing of the breech mechanism toward the breech. When the closing of the breech is initiated the velocity of the piston 52'is of course very slow and this-allows the liquid to pass the piston during the latters travel in the reduced diameter portion of the brake'cylinder adjacent the flange 56 with very little resistance and as the velocity mcreases the diameter of the cylinder also increases to effect the proper control. The size of the passage 38 is such as will prevent too high swinging velocities of the mechanism; After the cam devices M and N havecompleted their coaction and the plug threads arepartially engaged with the breech chamber threads the piston 52 enters the reduced diameter portion at the reservoir end of the chamber 57 and the necessary braking effect plug -gently to rest in fully locked position.

What I claim is 1. In a gun, the combination ofa movablecarrier, a rotatable breech plug, a motor for 40 moving the carrier and rotating the plug,

said motor including a reciprocating element; and a brake device including a reciprocatingelement rigidly connected to and movable with the reciprocatingelement of q the motor during the entire stroke of the-lat ter in either direction to control all movements of the plug and carrier'due to said, motor or gravitation.

i 2. In a gun, the combination of-a movable 60 carrier, a rotatable breech'plug, a motor for moving the carrier and rotating the plug, said motor including a cylinder and a piston, and a brake device including apiston rigidly connected to and movable with the motor pistonduring the entire stroke of the latter in either directionto-control all move ments of the plug and carrier due tosaid motoror gravitation. q

3. In a gun, the combination of a movable carrier, a rotatable breech plug, a, motor for moving the carrier and rotating the plug, said motor including a cylinder and piston, and a brake device disposed within the cylinder and including a piston rigidly cones, nected to and movable with the motor piston during'the entire stroke of the latter in either directionto control all movements of the plug and carrier due to said motor or gravitation.

4. In a gun, the combination of a movable breech mechanism, a motor for moving the breech mechanism to open and closed positions said motor including a cylinder and.

piston one of which is connected to the gun and the other to the breech mechanism, and a brake device including a piston rigidly connected to and moving with the motor pismotor piston during the entire stroke of the.

latter in either direction to control all-movements of the plug and carrier due to said motor or gravitation.

6. In a gun, the combination of a movable breech mechanism, a motor for moving the breech-mechanism to open and closed'posi-" tions said mot r including a cylinder and a piston one of hich is connected to the gun and the other to the breech mechanism, a

hydraulic brake cylinder within the'motor and upon which the :motor. piston slides, and a brake piston slidable in the-brake cylinder and connected to the motor piston to control all movements of the breech mechanism due a to said motor or gravitation.

7. In a gun, the combination of a movable carrier, a rotatable breech plug, a motor for said motor. including a cylinder and piston, a hydraulic brake cylinder within the'motor moving the carrier and rotating the plug,

cylinder, a brake piston slidable in the brake cylinder, a. piston rod attached to the brake;

pistonand connected to themotor piston, a packing in one end of the brake cylinder through which the piston rod slides, and

means'for preventing the brake pressure being exerted againstthe packing during the stroke of the brake piston in the direction of the packing.

8. In a gun, carrier, a rotatable breech plug, a motor for moving the carrier and rotating the plug, said motor including a cylinder and a piston, a hydraulic brake cylinder within the -motoi cylinden a brake piston and piston rod slidable in the brake cylinder and connected to the motor, piston, said piston and piston rod having a by-pass opening at one lendtl iough the rear of the brake piston and at its other end through the side of the pis ton rod, a packing in one end of the brake cylinder through which the piston rod slides, and an annular flange on the inner wall f the combination of a movable I the carrier to hol I against rotation during movefnent of the latch out-of locking relation to the arm.

17. .In a gun, the combination with a movable carrier and a rotatablebreech plug,

of a shaft rotatably mounted on the carrier and operatively connected wvitlr the plug to rotate the latter,'means for moving the carrier and rotating the shaft, a stop on the carrier, a latch on the carrier, nonelastic means for operating the latch to and from locked position, and an arm on the shaft engaged by the stop and latch during the movement of the carrier between the, unlocking and locking rotative periods of'the plug to lock said shaft-against rotation in either direction. p

18. In a gun; the combination of a mov able carrier, a rotatable breech plug, a

shaft rotatably mounted on the carrier and.

provided with a latch face, connections between the shaft and plug whereby the rota- .tion of the former will rotate the latter,

means for moving the carrier and rotating the shaft, a latch on the carrier engageable locking rotation, said latch face being disposed out of engagement with the latch with said latch face during movement .of the carrier to lock the shaft against plug when the shaft is at the limit ofits plug unlocking rotation and the latch in locked position, means for moving the latch to 'locked and released positions during movement of the carrier, and means for holdingthe shaft at the limit of its plug unlocking rotation -during movementof the latch t and from locked position. 19. In a gun, the combination of a movable carrier, a rotatable breech plug, a shaft. "rotatably mounted on'the carrier and provided with a latch face, connections between the shaft and plugwhereby rotation of the former will rotate the latter, means for moving the carrier and rotating the shaft, alatch on the carrienengageable with said latch face during movement of the carrier to lock the shaft against plug locking rotation, said latch facebeing disposed out of.

engagement with the latchwhen the shaft is at the limit of its plug unlocking rotation and the latch in locked position, means for moving the latch to locked and released positions during movement of the carrier, means for holding the shaft at the limit of,

its plug unlocking rotation during m'ove-' ment of 'the"latch to and. from locked position, and meansfor progressively releasing said holding means after the latch has assumed its locked position to permit said latclfi face to gradually contact with the late, 7

non-elastic means operatin carrier for locking the shaft against rotation during, movement of the carrier and automatically to move the latch to and rom locked position during movement of the carrier.

21. In a gun, the combination of a movable carrier, a rotatable breech plug, a shaft rotatably mounted on the carrier, means for rotating the shaft, a pitman having one end pivoted to the plug and its other end terminating in a cross-head bearing, a cross-head operatively mounted in said cross-head bearing, a crank on the shaft operatively connected to the cross-head, and means for moving the cross-head 'bearing fore and aft in harmony with the fore and aft movement of the breech plug due to the lead of the plug threads.

22. In a gun, the combination of a movable carrier, a rotatable breech plug, a shaft plug threads.

23. In a gun,the combination of a movable carrier, a rotatable breech plug, a shaft rotatably mounted on the carrier, means for rotating the shaft, a pitman having one end pivoted to'the plug and its other end terminating in a cross-head bearing, a cross-head in said bearing, and a crank on-the shaft oper'atively connected to the cross-head and detachablyinterlocking with thecross-head bearing to hold thecrank, cross-head and cross-head bearing in assembled relation.

24. In a gun, the combination of a movable carrier, a rotatable breech plug, a shaft rotatabIy mounted on the carrier, means for rotating the shaft, a pitman having one end pivoted to the plug and its other end terminating in a cross-head bearing, an inwardly directedfiange on the cross-head bearing, a cross-head in said bearing, a crank on the shaft operatively associated with the cross-head, and an extension on said crank engaged beneath the flange when the plug is locked to hold the} crank and cross-head bearing in assembled relation,

' said flange being disengageablefrom the exing in one direction to'efi'ect "disassembling ofthecrank and crossehead bearing.

the plug and gun."

. 25.- In a gun, the combinationof a movablecarrier, arotatable breech plug, coacting cam devices on the plug-and gun, a shaft rotatably mounted on the carrier and oper-', atively connected with the plug to rotate the vvlatter means for rotating the shaft and movirig the carrier, a roller mounted on the gun, and a cam fixed on the shaft vand co6perat-' i'ngwiththe roller to-render the movements of. the shaft corresponding to themovements' of the plug produced by the cam devices on- 1 26; In a gun, the combination of a movable carrier, a rotatable breech plug, a shaft rotatably mounted on the cari'ier'and Open 1' a atively connected to the plug, a cam on the signature in ishaft, nd. an element mounted, wh

rotation of the breech.

able carrier, a rotatable breech. plug, "a shaft.

the earn as the plug enters the'breech to in'iv In testimony whereofl hereunto jaiiix my the'presence of two witnesses; DORSEYJ fi Witnesses: p HENRY LI. BRIGHT,

- A. G. LEEG'H, Jr. 5

tiate locking rotation of 831d plug and dur-' 30- .ing' unlocking rotation of the'fplug to initiate opening movement of the carrier.

20 and coacting with the said cam-to initiate plug as the latterlenters the v 

